APOE and Alzheimer disease: Thus, several pathological aspects of AD, such as APP/Aβ pathways, APOE4 and lipid metabolism, tau-dependent pathologies and even PI3K signaling or iron metabolism are under investigation as potential therapeutic targets due to their effects in myelin homeostasis (Hardy and Selkoe, 2002; Mahley and Huang, 2012; Ballatore et al., 2007; Talbot and Wang, 2014; Smith et al., 2010).